At 04:33 AM 2010-04-11, Michael Biel wrote:
>I have received an email back from THE Magnetophon expert, Friedrich 
>Engel,  restating to me the answer I already knew:: the Germans did 
>not make paper tape.  Here is his answer:
> >> The first tapes on cellulose acetate, coated with carbonyl iron, 
> made between about 1933 and 1935, suffered from poor experience 
> with these material in the Ludwigshafen plant (... why did'nt they 
> ask the I.G. Faren colleagues at Agfa Wolfen works? ...), so these 
> tapes indeed are very brittle today. Richard Hess, years ago, asked 
> me about a sample of grey tape he found in Jack Mullins collection, 
> which turned out to be carbonyl iron tape (visiting Jack Mullin in 
> 1987 he showed me this tape!). R.H. apparently was able to play 
> back the tape, but, if I remember correctly, he had some problems 
> with breaks and ruptures. <<

Hello, Michael, Art, and Friedrich,

To set the record straight, the carbonyl iron tape that is in the 
Jack Mullin family collection did cause problems, but Herr Engel 
graciously suggested a re-hydration technique. When I first looked at 
it it was so cupped that it would stand out a half metre or so before 
folding over of its own weight, just like a carpenter's steel tape 
measure that is cupped for the reason that it needs to stay straight.

After the hydration technique (about 24 h in approx 100 % relative 
humidity at room temperature), the tape was like a satin ribbon and 
showed no signs of cupping. It did not break.

I have to further add, however, that this was the biggest success I 
have had at re-hydration. Of the few acetate tapes (more abused but 
not as old as this one) that I have tried it on, I have never had the 
spectacular success that I had with this one carbonyl iron tape.

The later acetate tapes (Magnetophonband Typ C) that I have 
transferred have varied in condition substantially. The worst were 
the Tonshrieber B tapes that had been stored in sealed steel cans.

The PVC homogeneous Magnetophonband Typ L had generally held up well, 
although one reel had the tendency to tear diagonally with tears of 
0.2 - 0.5 m which made reassembly difficult. Very  slow winding 
solved that problem.

Shiffy, it was Michael Biel who contacted Herr Engel on this, not me.

Also, please note that Herr Engel's list of BASF/Agfa/IG Farben tapes 
is available at the Audio Engineering Society Historical Committee website.
There is a corresponding list for 3M products



Richard L. Hess                   email: [log in to unmask]
Aurora, Ontario, Canada       (905) 713 6733     1-877-TAPE-FIX
Detailed contact information:
Quality tape transfers -- even from hard-to-play tapes.